The invention relates to multi-hull boats and more specifically ones having retractable connecting beams that allow the stabilizing floats to be folded alongside the center hull for trailering or docking in a standard marina.
Wide beam has always been a problem with trimarans, and the Float Connection Assemblies as described in the related patents have solved this with a simple and effective method of retracting the stabilizing floats of a trimaran to be alongside the center hull for trailering, or for docking in a standard marina slip. This system is now widely used.
However, a problem with marina docking has been underwater marine growth on the retracted floats' sides. This can be overcome by varying the folded geometry of the Float Connection Assemblies as in the related patents, but there is still a need to use anti-fouling paint higher on the float sides than is preferred and the beams extending above and across the center hull deck tend to obstruct access along the deck when docked.
Other float retraction systems, such as the `swing wing` system allow retraction by the floats by pivoting aft about vertical pivot shafts on both the floats and the center hull. This allows a normal level of anti-fouling on the float. However, the structural problems with this system are not easy to overcome, plus the overall length of the boat is increased and may necessitate a larger, more expensive dock.
An early example of a trimaran that had retractable connecting beams is illustrated in the Lindsay U.S. Pat. No. 3,937,166. One of its major disadvantages was the fact the stabilizing floats in their retracted position allowed for underwater marine growth on the retracted floats sides. Also the inner ends of the connecting beam in their retracted position extended above and across the center hull deck tending to obstruct access along the deck when docked.
The Thurston U.S. Pat. No. 4,457,248 illustrates the use of retracted connecting beams in various embodiments. His structure in some embodiments had his beams extending above and across the center deck hull thereby obstructing access along the deck when docked. His structure also allows for excessive underwater marine growth on the retracted float sides when in their retracted position.
The Thurston U.S. Pat. No. 4,878,447 also has structure which exhibits the same characteristics as the two previously discussed patents.
It is an object of the invention to provide a novel retractable connecting beam for a trimaran that allows the stabilizing floats to be retracted in against the center hull for trailering or marina docking while maintaining a substantially unobstructed access along the deck of the center hull.
It is also an object of the invention to provide a novel retractable connecting beam for trimarans that allows the stabilizing float to be maintained substantially vertical while traveling from its extended position to its retracted position thereby preventing marine growth along the lateral sides of the stabilizing float.
It is another object of the invention to provide a novel retractable connecting beam for a trimaran that can be easily manufactured and installed.